如何在C＃中向COM对象添加功能？ [英] How can I add functionality to COM object in c#?

问题描述

我是COM和c＃的新手，我想向第三方程序公开的COM对象添加功能。

I am new to COM and c# and I would like to add functionality to a COM object that is exposed by a third-party program.

最初，我的意图是从COM对象类继承，但是我发现它不是那么简单（例如，此处）。

Initially my intention was to inherit from the COM object class, but I found out it was not so straight forward (for example here).

目前，我有两个界面（即 IComAuto 和 ComAuto ）和关联的类（ ComAutoClass ）。

Presently, I have two interfaces (namely IComAuto and ComAuto) and an associated class (ComAutoClass).

要将自定义方法添加到 ComAuto 对象，我创建了一个类 ComObjectWrapper ，该类从该接口继承并通过存储 ComAuto

To add my custom methods to ComAuto objects, I have created a class ComObjectWrapper that inherits from this interface and implements it by storing a ComAuto object in a private field.

class ComObjectWrapper : ComAuto
{
    private readonly ComAuto ComObj;

    public ComObjectWrapper() : base()
    {
        ComObj = new ComAuto();
    }

    public short method1(object param)
    {
        return ComObj.method1(param);
    }
    ...
}

我有一种感觉这不是执行此操作的最佳方法，因为我需要将对原始方法的所有调用重定向到内部 ComAuto 对象。

I have a feeling this is not the best way to do this as I need to redirect any call to an original method to the internal ComAuto object.

我尝试通过设置 Embed Interop类型直接从 ComAutoClass 继承属性设置为 false 。当我已经编写的代码期望 string 时，这导致了一些方法以 object 的形式返回值。因此，我将不得不遍历所有编写的代码，以对 string 添加一些强制类型转换。这不是很理想，而且我对嵌入式Interop类型并不完全了解。

I tried alternatively to inherit from ComAutoClass directly by setting the Embed Interop types property to false in VS2015. This led some method to return values as object when the code I have already written expects string. I would therefore have to go through all the written code to add some casts to string. Not ideal and moreover I don't have a full understanding of what Embed Interop types is.

我会很感激如果有人可以对此有所启发或指向一些有用的文章（到目前为止，我在MSDN上发现的内容对于像我这样的初学者来说有点神秘）。

I would appreciate if anyone could shed some light on this or point to some useful article (what I have found so far on MSDN sounds a bit cryptic for a beginner like me).

推荐答案

听起来像扩展方法：

public static class ComAutoExtensions
{
    public static short Method1( this ComAuto com, object param )
    {
        return com.GetShortValue( param );
    }
}

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